New AssignTargetDevices pass to replace the legacy one.
The legacy pass has been moved aside so that the old flags still work
but will be removed in the future.
diff --git a/samples/transform_dialect/example_module.mlir b/samples/transform_dialect/example_module.mlir
index 585bb25..017f393 100644
--- a/samples/transform_dialect/example_module.mlir
+++ b/samples/transform_dialect/example_module.mlir
@@ -35,7 +35,7 @@
       #hal.executable.target<"vulkan-spirv", "vulkan-spirv-fb", {
         iree.gpu.target = #target
       }>
-    ]>
+    ]> : !hal.device
   ]
 } {
   hal.executable private @example_module_dispatch_0 {